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61.
Epidemic isolates of Vibrio cholerae 0139 express antigenically distinct types of colonization pili 总被引:2,自引:0,他引:2
T.K. Sengupta D.K. Sengupta G. Balakrish Nair Asoke C. Ghose 《FEMS microbiology letters》1994,118(3):265-271
Abstract Vibrio cholerae belonging to the recently described serogroup 0139, which are responsible for the current cholera epidemics in India and Bangladesh, were shown to express pilus-like structures partially cross-reacting with the toxin-coregulated pilus of V. cholerae strain (0395) belonging to the 01 serogroup and classical biotype. The 0139 pili were composed of 20 kDa subunit proteins which were antigenically related to the 20 kDa pilus protein of another diarrhoeagenic non-01 V. cholerae strain (serogroup 034) isolated earlier. The pili described in this study were found to be involved in the intestinal colonization process and, therefore, may contribute towards the virulence of the 0139 epidemic isolates. 相似文献
62.
A study was conducted to rapidly fractionate bovine spermatozoa on the basis of cell-surface H-Y antigen (i.e., Y chromosome-bearing spermatozoa). A novel, rapid immunomagnetic method was developed for removal of spermatozoa that bound to anti-H-Y IgG. Fluorescent labeling and flow cytometry were used to measure the efficiency with which spermatozoa binding to anti-H-Y were removed by the immunomagnetic technique. Washed bovine spermatozoa (n=7 bulls) were treated with a mouse monoclonal IgG antibody to H-Y antigen (MoAb 12/49). Fluorescent labeled goat antibody against mouse IgG was added to label those spermatozoa with cell-surface H-Y antigens. Supermagnetized polymer beads coated with an anti-antibody to the MoAb 12/49 were then added to the spermatozoa. After 20 min of incubation, spermatozoa were exposed for 2 min to a magnet, causing the magnetized particles to adhere to the sides of the tube. Nonmagnetized spermatozoa in the supernatent were aspirated and analyzed for fluorescent label by flow cytometry. Approximately 50% of spermatozoa not subjected to immunomagnetic separation were fluorescent labeled, and about one-half of the spermatozoa were observed microscopically to be bound to the magnetized polymer beads prior to magnetic separation (P<0.05). Following magnetic separation, only 1.2% (P<0.05) of the spermatozoa in the magnetic supernatent were fluorescent labeled. Assuming that only Y chromosome-bearing spermatozoa have cell-surface H-Y antigens, the present immunomagnetic fractionation removed almost all of the Y chromosome-bearing spermatozoa, leaving a population that was greater than 98% X chromosome-bearing spermatozoa. 相似文献
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65.
本实验用免疫印迹法纯化的抗EBNA亚型抗体,结合显微荧光分光光度检测技术,检测在不同感染状态下,三种亚型EBNA抗原在细胞中的表达程度。结果表明,处于潜伏感染状态下的Raji细胞EBNA-1表达量较大,经巴豆油和正丁酸诱导进入钝挫感染状态后EBNA-1表达减少,而EBNA-2的表达增强。B_(95-8)细胞也有相似的趋势。表明EB病毒的激活可能与不同EBNA亚型表达量的改变有关。 相似文献
66.
Andrea Casasco Marco Casasco Antonia Lcaro Cornaglia Marco Danova Monica Giordano Alberto Calligaro 《Biotechnic & histochemistry》1994,69(2):112-117
PC10 is a monoclonal antibody to proliferating cell nuclear antigen, a nuclear protein associated with the cell cycle. We have evaluated the effects of tissue fixation on PC10 immunoreactivity in sections of paraffin embedded rat tissues. Immunoreactivity was well preserved in tissues after fixation with alcohol-based solutions for 3-24 hr. Fewer PC10-positive cells were detectable in samples fixed with formaldehydecontaining solutions compared with samples fixed with alcohol for the same time. Loss of PC10 immunoreactivity in formaldehyde fixed tissues was progressive, and quantifiable as early as after 3 hr fixation. Consequently, alcohol-based fixatives are strongly recommended for any immunocytochemical prospective study using PC10 antibody. In contrast, loss of PC10-immunoreactivity is always predictable, but difficult to quantitate, using formaldehyde fixed specimens. This aspect should be considered when using PC10 antibody in retrospective studies with routinely-processed archival material. 相似文献
67.
Summary The occurrence of cells resembling mammalian Langerhans cells in the avian epidermis was studied by ATPase histochemistry, Ia immunoreactivity and electron microscopy. The existence of MHC class II antigen-(Ia) expressing, ATPase-positive dendritic cells, which are ultrastructurally similar to mammalian Langerhans cells except for the absence of Birbeck granules, was demonstrated. These cells may be a basic component of the immune system of birds. 相似文献
68.
以抗CEA、EGF-γ和血型前体Y配基抗原的单抗进行分析,结果表明:结肠癌组织中表达CEA和血型前体Y配基较强,而EGF-γ表达水平极低;进一步鉴定分析,识别血型前体Y配基抗原决定簇的单抗C_(14)与肿瘤具有较好的反应性。并发现这种决定簇存在于各种生物大分子中,包括以糖蛋白和糖脂形式存在,并表达于EGF-γ与CEA分子中。这一结果提示血型前体抗原过量表达于肿瘤细胞中,不但是血型组织相容抗原,可能也参与到一些特殊生物分子中,应深入研究和鉴定其功能。 相似文献
69.
Peter J. M. Hendriksen Marion Tieman Tette Van Der Lende Lawrence A. Johnson 《Molecular reproduction and development》1993,35(2):189-196
Studies designed to answer the question whether or not H-Y antigen is preferentially expressed on Y chromosome bearing sperm have resulted in conflicting results. This is probably due to the absence of reliable methods for estimating the percentage of X and Y chromosome bearing sperm in fractions, enriched or depleted for H-Y antigen positive sperm. In recent years a reliable method for separating X and Y chromosome bearing sperm has been published. With this method, separation is achieved by using a flow cytometer/cell sorter, which detects differences in DNA content. This technique provided the first opportunity for testing anti-H-Y antibody binding to fractions enriched for X and Y chromosme bearing sperm, directly. A total of 7 anti-H-Y monoclonal antibodies were tested using sorted porcine sperm and in one experiment also sorted bovine sperm. All monoclonal antibodies bound only a fraction of the sperm (20 to 50%). However, no difference in binding to the X and Y sperm enriched fractions was found. Therefore, the present experiments do not yield evidence that H-Y antigen is preferentially expressed in Y chromosome bearing sperm. © 1993 Wiley-Liss, Inc. 相似文献
70.
Bruce F. Giffin Kuixiong Gao Randal E. Morris Robert R. Cardell 《Biotechnic & histochemistry》1993,68(6):309-315
We report a modification of the immunogold-silver staining method (IGSS) for localizing hepatic phosphoenolpyruvate carboxykinase (PEPCK) in tissue sections, and we compare the efficacy of localizing the primary antibody with either a 5 nm gold labeled secondary antibody or 5 nm gold labeled secondary and tertiary antibodies. Light microscope examination of 10 μm frozen sections demonstrated that the use of combined secondary and tertiary gold labeled antibodies was superior to using a secondary gold labeled antibody alone. The increased labeling density (number of colloidal gold particles/antigenic site/cell) achieved by combined gold labeled antibodies was confirmed by electron microscopy. The increased labeling density resulted in a two-thirds reduction in the time needed for the IGSS physical development of the silver shells and less background. We achieved intense specific staining of hepatocytes expressing PEPCK while minimizing background staining. The use of combined secondary and tertiary gold labeled antibodies enhances the signal-to-noise ratio, achieves high resolution and is a suitable method for use in both light and electron microscopy. 相似文献